20111

Appears in sequences

• Composite numbers with four prime factors (not necessarily distinct) whose concatenation yields a palindrome.at n=13A046453
• Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 22 (most significant digit on right).at n=12A061975
• Łukasiewicz word for each rooted plane tree (interpretation e in Stanley's exercise 19) encoded by A014486 (or A063171), with the last leaf implicit, i.e., these words are given without the last trailing zero, except for the null tree which is encoded as 0.at n=36A071153
• Totally balanced decimal numbers: if we assign the weight w(d) = d-1 to each digit d (i.e., w(0) = -1, w(1) = 0, ..., w(9) = 8) and then read the digits of the term from left to right, the partial sum of the weights is never negative and the total weighted sum is zero.at n=36A071154
• Łukasiewicz words that are also valid asynchronic siteswap juggling patterns.at n=23A071160
• Integers whose decimal expansion satisfies the condition that if we read each term from the left to right (the most significant to the least significant digit) then each nonzero digit gives a distance to the next nonzero digit to right (with a cyclic wrap-over from the least-significant to the most significant nonzero digit).at n=24A071161
• a(n) = n*(14*n^2 - 21*n + 13)/6.at n=21A071229
• "Lazy binary" representation of n. Also called redundant binary representation of n.at n=39A089591
• Indices of terms in A091074 which are prime numbers.at n=38A091076
• One quarter of the number of n X n nonnegative integer arrays with every 2 X 2 subblock summing to 3.at n=7A145013
• Positive numbers y such that y^2 is of the form x^2+(x+119)^2 with integer x.at n=31A156650
• Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.at n=57A172360
• Triangle read by rows: T(n,k) = round(c(n)/(c(k)*c(n-k))) where c are partial products of a sequence defined in comments.at n=63A172360
• Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2.at n=17A180815
• Expansion of 1 / (1 - x - x^3 + x^6) in powers of x.at n=35A193771
• Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00001011.at n=10A260277
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 157", based on the 5-celled von Neumann neighborhood.at n=28A279470
• Expansion of Product_{k>=1} 1/(1 - k*x^(k^2))^k.at n=33A285243
• a(n) = n^2*(n*(4*n + 3) + 3*n*(-1)^n - 4)/96.at n=25A302758
• Expansion of Product_{k>=1} (1 + x^k)^(sigma_1(k)-k), where sigma_1(k) = sum of divisors of k (A000203).at n=29A319107